4.1 Hydrocarbon Cases Play Many Roles

In supermarkets, “remote” refrigerated display cases have typically been linked through piping networks to compressor racks or condensing units outside of the sales area.

However, another option is so-called plug-in cases with internal condensing units that employ small amounts of hydrocarbon refrigerant, notably R290 or, to a lesser degree, isobutane (R600a) or propylene (R1270). These self-contained cases are typically easier and less expensive to install, maintain and replace than remote systems, allow flexible merchandising and offer low-energy consumption as well as residual heat reuse for the store’s heating and hot water.

Notably, hydrocarbons represent a substantial and growing share of the refrigerants used in the marketplace. According to data from Embraco (a brand of Nidec Global Appliance), hydrocarbons accounted for 72% of the refrigerant market share, with HFCs taking up 18% in 2021; in 2025 hydrocarbons’ share will grow to 83% and in 2030 to 96%, says Embraco.82

Most hydrocarbon cases are air-cooled, but a growing number, so-called semi plug-in cases, use a water-loop (glycol) system to remove the heat from lines of contiguous cases.

In large stores, R290 cases are employed as spot merchandisers – front-end beverage coolers or horizontal bunker cases – supplementing the central refrigeration system. They can also be used to replace outdated remote HFC cases – which improves the capacity of the HFC rack – as well as old self-contained HFC cases or be installed in an expansion/remodel. Thus, they are seen as an inexpensive way to shift a large store to natural refrigerants without investing in a new rack system.

In a growing number of small stores – including grocery, convenience, dollar and even drug stores – hydrocarbon units are being installed throughout the sales floor (and in a growing number of locations, in cold rooms). In Europe, chains like Waitrose in the U.K., Colruyt in Belgium and Germany-based Lidl have installed hydrocarbon units store-wide. In the U.S., Wild Fork Foods, a small Florida chain, is an example of a retailer that has taken this approach.

Some observers believe that many stores, particu- larly larger ones, will end up using a combination of CO2 and R290, with CO2 serving the perimeter and cold rooms, and R290 accommodating the center and front of the store. This would considerably reduce piping from the CO2 rack system.

The hydrocarbon charge limit of 150g has not prevented the rapid expansion of the R290 display case market. However, the prospects for propane in commercial refrigeration improved when the International Electrotechnical Commission (IEC) increased the amount allowed in self- contained cases to 500g from 150g in 2019; this will potentially lower the cost of R290 equipment, particularly large cases. Regional standards bodies have adopted or are in the process of adopting the IEC model in whole or in part. (For the scenario in Europe, see page 35.)

One of the leading global providers of self-contained R290 cabinets is Austrian OEM AHT, which has been making these units for more than 15 years. A new development is AHT’s Active Monitoring System, which allows customers to monitor their cases to prevent food spoilage.

R290 in urban stores

In Europe, where many small-format stores have installed hydrocarbon cases throughout the sales floor, and often in the cold rooms, this trend will continue as more small stores are opened in urban areas. Large stores will use R290 cases in more places as a supplement to remote cases.